"Stretch or not strech" of aircraft designs

[Shortround6]

Or they could have just glued the turbocharger to the side like they did on the prototype

Prototype had the turbo on the bottom. Those lumpy, bumpy side scoops held the oil cooler and the intercooler, niether of which worked as desired.

 

[Schweik]

Yes, overclaiming was universal, but how much other airforces were overclaiming has no bearing on the P-39 i Soviet service. The success of the P-39 on the the Eastern Front is based on the claims of the Soviet pilots, i.e. how well they thought they were doing; that is what overclaiming does, distorting the perception of what was really achieved. What makes it so difficult to evaluate is the seeming lack of data; how many enemy aircraft did Soviet P-39 pilots actually claim?

Well there are two logical flaws in this argument:

1. An assessment of how well a fighter aircraft did in combat is based on a combination of how many enemy aircraft were destroyed vs. how many friendly aircraft lost. German claims (and overclaiming) are relevant to the latter.
2. The downplaying of Soviet victory rates is based on the notion that they overclaimed far more than anyone else. This is subject to interpretation but is probably substantially overstated. And the ratio of German overclaiming is relevant to the claim.

Because Soviet claims with the P-39 are probably two orders of magnitude higher than any other nation (bBased on Soviet records and claims they were at least on par with German fighters) to believe that the Soviet P-39s really didn't do so well, we have to assume that their overclaiming, particularly with P-39 units, was far in excess of anyone else. In other words, if for example there was one (1) US P-39 Ace, vs. hundreds for the Soviets, we can assume the ratio of total victories is at least in that ballpark (I do not know the total number of claims by type in Soviet use in WW2, I would love to see that if anyone has it).

The truth is while they did overclaim significantly more in the first year or so of the war, by the time the P-39s were in action on a large scale this was coming under control. Though about 150 Airacobras donated by Britain were operating in the North and a few dozen in the Central Front zone around mid 1942, most of the Airacobras (I believe all of the American ones) went into action in the South and Central Fronts in early 1943.

Southern Front
The first unit to convert to P-39s in the South was 298 IAP (later became a 'Guards' unit 104 GIAP) went to action in January 1943. They claimed 167 victories for 30 aircraft lost.
45 IAP (later 100 GIAP) went into action in March 1943,
16 GIAP began transitioning from Yak-1s to Kobras in January of 43 and fought their first action with P-39s on March 11, 1943 (another source says 9 April 1943). They became one of the top 3 regiments in the VVS. They were also the first of the three to convert to pairs instead of flights of 3. Their ranks included 15 HSU and two double HSU including Aleksandr Pokryshkin (who scored 48 individual victories in his Kobra), Grigorii Rechkalov (56 individual victories mostly in P-39), and Vadem Fedaev (17 individual victories before being shot down in 1943) and Alexandr Klubov (31 individual victories). During their fighing in the Kuban the Soviets had instituted the practice of only verifying victories by recovery of the identity plates* (this invalided 17 victories for Pokryshkin for example).

Central Front
153 IAP was briefly in action in June 1942 as a test, (claiming 64 German aircraft for 8 loses) was pulled out of the line and put back in as 28 GIAP during Dec 1942. They claimed a further 63 victories for 19 aircraft lost in combat.
30 GIAP (previously 180 IAP) started in November 1942 and fought over Kursk. THey claimed 581 victories during the war and had more than ten HSU.
185 IAP and 494 IAP also went into action in mid 1942 but did poorly and were pulled out, 185 IAP becoming a ferry squadron (probably a very lucky development for their pilots!)
9 GIAP which used P-39s from August 1943 through July 1944.
27 IAP went into action in March 1943.

So the majority of the Soviet P-39s were actually in action from 1943 by which time overclaiming had significantly diminished. Even if you assume that they were overclaiming at an unusually high rate of say 3-1, and even taking into consideration some units like 185 and 494 IAP didn't do well, overall the Soviet units still had an extraordinary rate of success compared to all other Allied units flying the P-39. So there is something there to figure out.

Some links:

Bell P-39 Airacobra in Soviet Service
P-39 Airacobras related to G.A. Rechkalov, 16 GIAP
Early Versions of Airacobra Aircraft in Soviet Aviation. Part 2 – Lend-Lease

* During the Kuban operation 16 GIAP claimed 71 x Bf 109s, 2 x Fw 190s, 4 x Ju 88s, 1 x Do-17 and 1 x Ju 87, for a total of 77 victory claims. During the same operation they lost 13 airacobras shot down on missions or 'failed to return', plus 2 in accidents, and lost 11 pilots. Most of their earlier model P-39D were lost in the battle. Just because they recovered identity plates does not necessarily ensure that all of their claims were valid but they did probably do better than even against the Germans in this battle.

 

[Schweik]

Well, this theory flies in the face of what we know about Soviet engine development.
(snip)
Back in 1940 there was a project for the M-106TK with two TK-1 turbo superchargers. The Soviets tried to put turbochargers on just about everything short of a T-34 tank. However their metallurgy/manufacturing failed them and none of the turbo installations saw service during the war.

Because they concentrated on the low altitude aircraft, does not mean that they completely ignored high altitude or long range planes. They knew eventually they might need them and as you have so often pointed out, if you do suddenly need to put a lot more money and effort into a fundamentally new type of warplane, you need to have some preliminary work already done.

But as an analogy - both the Germans and the Soviets spent some time and money developing four engine long range heavy bombers, (the Amerika bomber project - initially planned in 1938, serious development from 1942 - and the Pe-8 - first flight 1936 - as examples) but neither really followed up on this because for both the Tactical fighting on the front between them became the most important problem they faced. By 1943 the Germans had the added motivation of contending with high flying four engined bombers which is why they continued to develop their high altitude fighters and tried to arm them as heavily as they could (more heavily than the Soviets needed to.

You also have the whole Mig-1/3 saga which morphed into the I-230 and I-220 aircraft, some of which had pressure cabins and turbo superchargers on AM-39 engines.
I would also note that early Lagg fighters were supposed to have a 23mm cannon and two 12.7mm machine guns but the 23mm cannon didn't meet expectations and was replaced by the smaller 20mm gun, Some early Lagg-3s were 5 gun fighters. The single 20mm, two 12.7mm guns above the engine and two 7.62 ShKAS machine guns under the engine. As with many Soviet aircraft production examples showed a much decreased performance from prototypes and drastic measures had to be taken to restore performance. Like taking out guns and restricting ammo.

Drastic measures also because at the top of their opponents arsenal they faced one of the swiftest aircraft in the war in the Bf 109. Speed became a major priority, far more than heavy armament.

The Russians were designing mostly wooden fighters (and mixed construction larger aircraft) well before the Germans invaded to due a lack of Aluminum in peace time. This was not a brilliant decision made by the Russians during the war but rather a situation forced on them by the supply situation well before the war.

I never claimed brilliance let alone prescience, but expediency and pragmatism. The Soviets followed a very tight schedule of the allocation of their resources at least in aircraft development. No more than needed for the mission. A longer ranged, high altitude, heavily armed fighter would have been beyond their needs, (otherwise they would have liked the P-478 a lot more than they did, and perhaps emulated it).

Lets not forget, if their engines were really so cripplingly weak they could have A) spent a lot more time and effort developing more powerful and higher flying engines, or B) taken thousands of Merlin and Allison (and even Wright 2600) engines out of Lend Lease planes they had received and put them in their own, or C) reverse engineered the Lend Lease engines the way they did with the B-29. I think it's far more likely that they just decided they had what they needed with the Klimov M-105 and were satisfied with the pace of development of their engines, compared to the need to produce huge numbers of Yak-1s and 7s in the early war, and later their Yak-9s and La 5s.

 

[michael rauls]

Yes, overclaiming was universal, but how much other airforces were overclaiming has no bearing on the P-39 i Soviet service. The success of the P-39 on the the Eastern Front is based on the claims of the Soviet pilots, i.e. how well they thought they were doing; that is what overclaiming does, distorting the perception of what was really achieved. What makes it so difficult to evaluate is the seeming lack of data; how many enemy aircraft did Soviet P-39 pilots actually claim?

Shurley you're correct that overclaiming distorts the picture of what's really happened.
No disagreement from me there but the discussion was, at least as I understood it, how effective was the p39 compaired to other aircraft, largely the p40 but also various Russian types. Unless there is a great disparity in the overclaiming rates of Russian pilots and those of other nations( and if an average is taken throughout the war they seem to have been similar) then shweiks statement that the Germans overclaimed also meant, at least to me, that in a comparative sense( the only sense that in my mind at least is valid as aircraft did not oparate in a vacuum) the claims cannot just be dismissed as overclaiming and the p39, or any other aircraft concluded as ineffective to whatever degree as one would have to then do the same to every aircraft and you just end right back where you started. Imho

 

[Schweik]

(surely)

 

[Schweik]

There is actually a pretty big difference in power level between a MG 151/15 and a Breda 12.7 mm....
Here is a little bit of background on the Macchi C.202 and its production 'standard':

Serie I – Breda 100 Aircraft 2 x 12.7 mm – same as prototype
Serie II – Macchi 10 Aircraft 2 x 12.7 mm – same as prototype
Serie III – Macchi 140 Aircraft
Serie IV – SAI Ambrosini 50 Aircraft
Serie V – SAI Ambrosini 50 Aircraft
Serie VI – Breda 50 Aircraft
Serie VII – Macchi 100 Aircraft 2 x 12.7 mm & 2 x 7.7 mm – April 1942
Serie VIII – Breda 50 Aircraft
Serie IX – Macchi 100 Aircraft – Sep 1941
Serie X – Breda 100 Aircraft
Serie XI – Breda 150 Aircraft
Serie XII – Breda 150 Aircraft
Serie XIII – Macchi 50 Aircraft
Serie XIV and later not built due to surrender.

The Serie VII and "later" were the only versions to come from the factory with wing armament.
Some earlier versions were retrofitted, but many factory wing guns were removed for the simple reason that they were determined to be ineffective and adversely affected the aircraft's flying characteristics. Loaded weight increased from 2930 KG to 3069 KG (!).
That is the choice when there isn't sufficient engine power.
So, total production of 1150 aircraft only had 600 equipped with the wing guns from the factory although some had them added and some had them removed,

I know there is a difference between MG 151 and Breda, but I don't think it's so much that if an MC 202 is behind you, you are safe. Nor do I think it's more than twice the difference (i.e. one Mg 151 is better than two Breda 12.7mm) because each bullet from either gun can kill a pilot, destroy and engine or cripple an aircraft. Mg 151 shoots 650-750 rpm or roughly 11 rounds per second, Breda-SAFAT 12.7mm shoots 575 rpm (synchronized), which for two guns works out to 1,150 rounds per minute, 19 rounds per second. I know the Mg 151 shoots a better round, but any aircraft struck by 10 or 20 HMG bullets is in danger of destruction. Nose guns are more accurate than wing guns.

Whether or not MC 202 had wing guns could be decided in the field and really depended on the mission profile (what kind of enemies were they contending with). For example against P-38s they might remove wing guns for better high altitude performance. Against Boston or Baltimore bombers they might add them back in.

The precise number of guns notwithstanding, if your assertion is indeed that the MC 202 was an inferior aircraft below the capability of contemporaneous Bf 109s and more comparable with say CR 42, Fiat G.50 or MC 200 you would be taking an outlier position very much at odds with most (if not all) of the pilots who flew with and against them. Most Spitfire pilots operating in the MTO certainly didn't feel that way, and the ratio of victories (as verified by books which show losses on both sides) indicates they were at parity.

If you are really discussing tactics, all that proves is that the P-40K can lose altitude fast and get down to its comfort zone.
An opponent would be stupid to follow when the P-40 has gone completely defensive and can be BnZ'ed at will.
Even a short zoom climb would take it out of its best performance altitude.

And this was the tradeoff. Bf 109 could disengage with a swift climb, but the P-40 could disengage with a dive (especially after mid 1942 by which time it had become dangerous to engage them at low altitude). Being able to disengage was key to survival in a fighter in WW2 (I think the reason Hurricanes did so poorly in air to air combat against the Bf 109 was because while they could turn to avoid a given pass, they really had no way to disengage).

Attacking from above gave the Germans the intitiative, but this was not the same as saying guarantee of victory. For one thing, the Anglo-Americans developed tactics (the whole squadron making a high power turn guns blazing into all attacks from above as an initial response) which effectively dissuaded the previously successful Axis "snipe and climb" tactics (so long as they were spotted in time). Second, whether the Germans could retain their advantage at high altitude all depended on what they were fighting over which usually meant bombers.

If the situation was that the P-40s were escorting B-25 or Baltimore bombers or fighter bombers, and the Germans needed to stop the latter (for example if they were attacking their own airfield) then the Axis fighters had to little choice but to get down to altitude and mix it up. They could still often disengage with a climb but it wasn't as easy or safe well within the performance envelope of the Allied fighters. As General Benjamin O. Davis of the 99th FS ("Tuskegee") who flew the P-40F/L (and P-39s, P-47s and P-51s) in WW2 and also flew F-86s in Korea, said this about the P-40s:

"The P-40 operations in the Pacific and Europe were much like the F-86 and the MiG in Korea. All the MiG's had to do was stay away from the F-86's; yet we had an eleven-to-one kill ratio of F-86's over MiG's. Same thing with the P-40 and the Me 109. If the German fighters wanted to stay away, the P-40's couldn't get them. When the Me 109's came down to engage the P-40's we were superior."

Based on pilot anecdotes Allied (particularly Commonwealth) pilots also routinely used the extra power in the P-40K specifically to catch overflying Bf 109s. For example this anecdote from Aussie Ace Bobby Gibbes shows the P-40K had more power avaialble at lower altitudes than the (merlin powerted) Kittyhawk II:

"Well I was a poor shot. Air to ground I think I was a very good shot. I could group my bullets and make sure they didn't run through. I could hold them on target while I went in and strafed. But air to air I certainly missed an awful lot of aeroplanes I fired at. I think the classic example was one day when I had a Kitty Mark III - I had acquired it illegally, I might say - and I had to give it back to the RAF later - but I had a little bit more horsepower than the rest of the squadron and when three 109s passed overhead or ahead of us, if I had waited to take the squadron with me, which normally I would have done, they would have got away.

But seeing them and knowing I had that bit more power I opened the taps and went after them. I had a look at the three of them and I thought, if I pull a lead on the number one, number three could probably get a deflection shot at me, so I thought, well, I'll get number two first. So I fired at number two. I must have misjudged their speed completely because the one behind, probably fifty yards behind, flicked over and went down smoking like hell. I looked round to see who else had shot at it but I was the only one in the sky. I then decided, well, I'll go after the number one and number two but, of course, they didn't wait for me. The one, incidentally, number three, did go in.

Yes, it was a successful mission. We had a big celebration that night in the squadron and a few of the 'Yanks' came over and they thought the shooting was quite brilliant and I had only fired very few rounds. However, during the night I managed to get quite a few grogs on board and I decided that I'd confess that I hadn't even aimed at that one, I'd aimed at the one ahead of it. And, of course, when I did tell them of course no one believed me, but it was true."

We are mostly in agreement. Golodnikov contradicts himself quite a lot. The key point to take early in the interview is his mention of over-revving the engine. Can't hardly take that one back.

Lets remember Golodnikov only mentions over revving, I think he said 3,200 RPM? He didn't specifically mentioning higher boost (though like you I assume he also meant that). And he's not the only source we have, the other big article on the lend lease site about the P-40 mentions a lot of engine trouble especially with the first few squadrons, but doesn't suggest quite so dismal of a life span for the engines later in the war. Nor did they have this kind of trouble wearing out engines on the P-39s.

This test aircraft may have started life as a P-40K, but if you actually read the report, you will find that it has had the engine replaced with a V-1710-81. This is NOT the V-1710-73 as normally installed in P-40K.

- Ivan.

You are right I made a mistake there, I missed the part about the engine swap. But I still stand by the notion that the P-40K was 'souped up'. I'll transcribe something else later when I have the time.

 

[Ivan1GFP]

Drastic measures also because at the top of their opponents arsenal they faced one of the swiftest aircraft in the war in the Bf 109. Speed became a major priority, far more than heavy armament.

Hello Schweik,

I believe you were more correct earlier. The Soviets were working close support for their ground forces for the most part and were stuck on the "Quantity has a quality all its own" mentality. I was reading through some of your links and the statement that the Airacobra Mk.I a speed of 306 MPH at Sea Level and 363 MPH @ 13,800 feet "making it as good as the Yak-3 and MiG-3 then in Russian production" also says a lot about those other two aircraft that are supposed to be about 35-40 MPH faster but apparently are not in actual service.
Note that these numbers for Airacobra Mk.I are pretty much in agreement with other well documented tests and at Sea Level is barely faster than the A6M2 on overboost.
If this was how well their best aircraft actually performed in the field, then later versions of the Airacobra must have been superstars in comparison.

I never claimed brilliance let alone prescience, but expediency and pragmatism. The Soviets followed a very tight schedule of the allocation of their resources at least in aircraft development. No more than needed for the mission. A longer ranged, high altitude, heavily armed fighter would have been beyond their needs, (otherwise they would have liked the P-478 a lot more than they did, and perhaps emulated it).

A service that is installing 37 mm and 45 mm cannon in single engine fighters is hardly one that is satisfied with "lightly armed" fighters.
As for copying the P-47, I don't believe they had the technology to manufacture the turbocharger and the aircraft really didn't suite their style of fighting. Soviet fighters tend to be small and agile with relatively good power to weight ratios and at least fair acceleration. The Thunderbolt was none of those. Even the hotrod P-47M was being outrun by P-51D in the initial acceleration as was described by the pilot of "Wonderful Winnie". In other words, the Thunderbolt would have had what they called a low "combat speed".

Lets not forget, if their engines were really so cripplingly weak they could have A) spent a lot more time and effort developing more powerful and higher flying engines, or B) taken thousands of Merlin and Allison (and even Wright 2600) engines out of Lend Lease planes they had received and put them in their own, or C) reverse engineered the Lend Lease engines the way they did with the B-29. I think it's far more likely that they just decided they had what they needed with the Klimov M-105 and were satisfied with the pace of development of their engines, compared to the need to produce huge numbers of Yak-1s and 7s in the early war, and later their Yak-9s and La 5s.

A) First of all, the Soviets DID spend a lot of time and effort in an attempt to get a more powerful inline into service. They just didn't have much success at it until late in the war.
B) Why spend the effort pulling an engine off a Lend-Lease aircraft when the whole aircraft is being supplied to you and the net result IF you are successful is that you get ONE aircraft instead of two. We have already discussed the short life spans of their engines in service, so it wasn't like there were going to be a lot of spares in good condition.
C) Remember the Soviet preference for Motor Cannon. None of the Lend-Lease engines could accept that setup except Airacobra but that required a remote mounted engine.... The copying of a B-29 was in a different time with different priorities and by that time, technology probably had improved a bit from its state during the war.
The fact that the Soviets kept trying to increase the power of the M-105 and kept trying the M-107 in tests throughout the war pretty much tells us that they were not satisfied with the performance of M-105.

I know there is a difference between MG 151 and Breda, but I don't think it's so much that if an MC 202 is behind you, you are safe. Nor do I think it's more than twice the difference (i.e. one Mg 151 is better than two Breda 12.7mm) because each bullet from either gun can kill a pilot, destroy and engine or cripple an aircraft. Mg 151 shoots 650-750 rpm or roughly 11 rounds per second, Breda-SAFAT 12.7mm shoots 575 rpm (synchronized), which for two guns works out to 1,150 rounds per minute, 19 rounds per second. I know the Mg 151 shoots a better round, but any aircraft struck by 10 or 20 HMG bullets is in danger of destruction. Nose guns are more accurate than wing guns.

The gun power isn't just a matter of rate of fire. The MG 151 has a MV of 960 M/S as compared to Breda 12.7 at 760 M/S.
The typical projectile also weighs about 75% more.... If it isn't twice as powerful, it is pretty close to that.

Whether or not MC 202 had wing guns could be decided in the field and really depended on the mission profile (what kind of enemies were they contending with). For example against P-38s they might remove wing guns for better high altitude performance. Against Boston or Baltimore bombers they might add them back in.

The passage I quoted about intercepting heavy bombers with usually just two machine guns was about killing B-24 Liberators which are obviously much easier to destroy. (?)

The precise number of guns notwithstanding, if your assertion is indeed that the MC 202 was an inferior aircraft below the capability of contemporaneous Bf 109s and more comparable with say CR 42, Fiat G.50 or MC 200 you would be taking an outlier position very much at odds with most (if not all) of the pilots who flew with and against them. Most Spitfire pilots operating in the MTO certainly didn't feel that way, and the ratio of victories (as verified by books which show losses on both sides) indicates they were at parity.

I never made that statement. My comment was although from performance numbers, it was pretty close to the 109F, its engine power was identical to the 109E, and no, I do not believe it was better than a 109F though the airframe had more potential for development.

As mentioned earlier, its reputation seems to me to be amazing considering how few aircraft there actually were in theater.
From January to December 1942, Italian fighters flew 23,555 sorties. About 30 percent were by Folgores.
There were only 30-70 Folgore as a monthly average in service in North Africa during this time.
This brings up the point I was getting at earlier: If THIS was the most plentiful modern fighter, then WHAT ELSE was flying all those sorties?

And this was the tradeoff. Bf 109 could disengage with a swift climb, but the P-40 could disengage with a dive (especially after mid 1942 by which time it had become dangerous to engage them at low altitude). Being able to disengage was key to survival in a fighter in WW2 (I think the reason Hurricanes did so poorly in air to air combat against the Bf 109 was because while they could turn to avoid a given pass, they really had no way to disengage).

That "disengage" is only temporary if the other fellow really wants you. The idea of maintaining energy is trading altitude for speed and converting that back to altitude, not bleeding it off puttering around near the ground. The fellow with the altitude can make high speed passes all day (or at least until he runs out of fuel) and keep the advantage.
I also don't believe the 109 could get away that easily with a simple swift climb. The P-40 probably also has a pretty decent zoom climb or at least close enough to get a shot if they start in similar states.

- Ivan.

 

[pinsog]

Prototype had the turbo on the bottom. Those lumpy, bumpy side scoops held the oil cooler and the intercooler, niether of which worked as desired.

I know, I was just joking around a bit.

Being serious now, when I look at the P39D on up, it had the lowest drag of any fighter besides the P51. Looks to me like you could put the turbocharger in the belly and add the 2 side scoops back in for the intercooler and oil cooler, give it 1150 HP at 25,000 feet and it should have been fine. The P38 had 4 of those big scoops, 2 on each boom, and it was still fast. Looks like keeping the turbocharger and side scoops while doing some wind tunnel work to get them right would have been the way to go. Didn't the prototype only make 1050 hp or so even with the turbocharger?

 

[Schweik]

Was there any reason for the mid-engine besides the giant 37mm gun? Maybe you could take that out and put the turbo in the nose...

 

[Shortround6]

Was there any reason for the mid-engine besides the giant 37mm gun?

Nope.

There was some claim about improving maneuverability by having the largest weight right on the CG but since it doesn't really affect roll and pretty much only affects pitch change and initial pitch change (or acceleration of pitch change) at that that seems a pretty dubious reason.

Early Spitfires had too much elevator response (pitch change) as it was with the engine in nose and the Hawk 75 seemed to have very good elevator response (in British tests) so having to stick the engine in the middle of plane seems an awful lot of work for little result if you are looking for other benefits (more streamline nose?) beside the big gun.

 

[Schweik]

Hello Schweik,

I believe you were more correct earlier. The Soviets were working close support for their ground forces for the most part and were stuck on the "Quantity has a quality all its own" mentality. I was reading through some of your links and the statement that the Airacobra Mk.I a speed of 306 MPH at Sea Level and 363 MPH @ 13,800 feet "making it as good as the Yak-3 and MiG-3 then in Russian production" also says a lot about those other two aircraft that are supposed to be about 35-40 MPH faster but apparently are not in actual service.
Note that these numbers for Airacobra Mk.I are pretty much in agreement with other well documented tests and at Sea Level is barely faster than the A6M2 on overboost.
If this was how well their best aircraft actually performed in the field, then later versions of the Airacobra must have been superstars in comparison.

If you think the P-39D was on par with the Yak-3 or that the Yak-3 only made 363 mph you are a bit off the mark. Either you made a typo or whoever you are quoting did I would assume they meant the Yak-1. P-39D was probably on par with the early Yak-1 which some units switched from to the P-39 as you can read in those articles I linked. It was certainly better than the MiG-3 which was considered below even the I-16 or LaGG-3. Most of the P-39s they used from 1943 were the later model variants, which had quite good performance (on paper at least).

A service that is installing 37 mm and 45 mm cannon in single engine fighters is hardly one that is satisfied with "lightly armed" fighters.

Ah, you are trying to get me coming and going eh? The 37mm is a big gun, but i think the reason they put it in was mostly for strafing tanks and as a quick way to put down something a little sturdier than usual like a Fw 190 fighter bomber variant or a Hs 129. But it was still (typically) only armed with 1 or 2 other guns.

The point is, they put exactly as much armament as they needed, no more no less. For shooting down fighters a hub mounted 20mm and one or two nose mounted HMG was plenty. Probably about the equivalent in effectiveness to the oft used four wing guns in so many US fighters, or the much maligned armament of the much maligned (but highly effective) Macchi 202, or the armament of (nearly identical but) highly praised Bf 109F series.

As for copying the P-47, I don't believe they had the technology to manufacture the turbocharger and the aircraft really didn't suite their style of fighting. Soviet fighters tend to be small and agile with relatively good power to weight ratios and at least fair acceleration. The Thunderbolt was none of those.

Well mate that is exactly my point. All the extra capability of the P-47 in terms of range, high altitude performance, payload etc. was basically useless from the Soviet point of view. How well can it cover our ground troops? How well can it escort the Sturmoviks? How well can it handle Bf 109G2 at 3,000 feet?

A) First of all, the Soviets DID spend a lot of time and effort in an attempt to get a more powerful inline into service. They just didn't have much success at it until late in the war.
B) Why spend the effort pulling an engine off a Lend-Lease aircraft when the whole aircraft is being supplied to you and the net result IF you are successful is that you get ONE aircraft instead of two. We have already discussed the short life spans of their engines in service, so it wasn't like there were going to be a lot of spares in good condition.
C) Remember the Soviet preference for Motor Cannon. None of the Lend-Lease engines could accept that setup except Airacobra but that required a remote mounted engine.... The copying of a B-29 was in a different time with different priorities and by that time, technology probably had improved a bit from its state during the war.
The fact that the Soviets kept trying to increase the power of the M-105 and kept trying the M-107 in tests throughout the war pretty much tells us that they were not satisfied with the performance of M-105.

Well, "a lot of time and effort" is a subjective concept. Are you really suggesting that they couldn't have reorganized priorities and got stronger engines in action more quickly if they had put enough emphasis on it? My argument is that the pace it moved was good enough as long as a Yak-1B can still shoot down Bf 109s.

The gun power isn't just a matter of rate of fire. The MG 151 has a MV of 960 M/S as compared to Breda 12.7 at 760 M/S.
The typical projectile also weighs about 75% more.... If it isn't twice as powerful, it is pretty close to that.

Right. Which adds up to their being roughly equal.

I never made that statement. My comment was although from performance numbers, it was pretty close to the 109F, its engine power was identical to the 109E, and no, I do not believe it was better than a 109F though the airframe had more potential for development.

I never said it was 'better', I said it was 'roughly equal'. Performance was clearly similar, armament was at most slightly inferior, agility was slightly superior and the 202 had slightly better wing loading. It probably came out even. Almost the same speed, climb rate, ceiling, range etc. etc.

As mentioned earlier, its reputation seems to me to be amazing considering how few aircraft there actually were in theater.
From January to December 1942, Italian fighters flew 23,555 sorties. About 30 percent were by Folgores.
There were only 30-70 Folgore as a monthly average in service in North Africa during this time.
This brings up the point I was getting at earlier: If THIS was the most plentiful modern fighter, then WHAT ELSE was flying all those sorties?

Maybe Pinnochio flying some Macchi M.14s?

Ok since you keep bringing it up, per Shores on November 1942, at the end of El Alamein, the actual (as in on-hand strength) TO&E for Italian fighters in the MTO Theater was:

Italians
Macchi 202

54° Stormo - 2
51° Stormo - 23
17° Gruppo CT - 33
153° Gruppo CT - 21
20° Gruppo CT - 11
4° Stormo CT - 28
3° Stormo CT - 20

RE 2001
22° Gruppo Aut CT - 21

Macchi 200
2° Stormo CT was listed as mixed MC 202 and 200 but doesn't list how many
54° stormo CT - 6

G.50bis
24° Gruppo Autonomo CT - 26
160° Gruppo Autonomo CT -7

So that is 138 x MC 202 on hand at that time, 21 x Re 2001, about 15 x MC 200, and 33 x G.50bis for a total of 207 fighters, 75% of which were top quality (MC 202 and Re 2001).

There were also 76 Cr 42s available but at that point they were only used as bombers and mostly flew at night. Very few were ever claimed by 1942 nor did they make any claims.

All this is from Meditteranean Air War Vol III pp 43-46. I think I have an earlier TO&E for them somewhere before the battle in which they had considerably more fighters but I'm having trouble finding it, Shores books lack sorely in useful chapter headings or a real index and being 600+ pages thick are a nuisance to search through trying to find anything.

That "disengage" is only temporary if the other fellow really wants you. The idea of maintaining energy is trading altitude for speed and converting that back to altitude, not bleeding it off puttering around near the ground. The fellow with the altitude can make high speed passes all day (or at least until he runs out of fuel) and keep the advantage.
I also don't believe the 109 could get away that easily with a simple swift climb. The P-40 probably also has a pretty decent zoom climb or at least close enough to get a shot if they start in similar states.

- Ivan.

The thing is if the P-40 dives and is chased by another pilot who really wants him, then at low altitude so long as it can extend sufficiently in the dive to turn around, you now have a new dogfight where the P-40 has a 200 hp advantage, turns better and may be a little faster. This is where a lot of Bf 109s and 202s got shot down. They were better off keeping the fight up above 20k if they could. Sometimes they couldn't such as when their own airbase was attacked.

 

[michael rauls]

If you think the P-39D was on par with the Yak-3 or that the Yak-3 only made 363 mph you are a bit off the mark. Either you made a typo or whoever you are quoting did I would assume they meant the Yak-1. P-39D was probably on par with the early Yak-1 which some units switched from to the P-39 as you can read in those articles I linked. It was certainly better than the MiG-3 which was considered below even the I-16 or LaGG-3. Most of the P-39s they used from 1943 were the later model variants, which had quite good performance (on paper at least).


Ah, you are trying to get me coming and going eh? The 37mm is a big gun, but i think the reason they put it in was mostly for strafing tanks and as a quick way to put down something a little sturdier than usual like a Fw 190 fighter bomber variant or a Hs 129. But it was still (typically) only armed with 1 or 2 other guns.

The point is, they put exactly as much armament as they needed, no more no less. For shooting down fighters a hub mounted 20mm and one or two nose mounted HMG was plenty. Probably about the equivalent in effectiveness to the oft used four wing guns in so many US fighters, or the much maligned armament of the much maligned (but highly effective) Macchi 202, or the armament of (nearly identical but) highly praised Bf 109F series.



Well mate that is exactly my point. All the extra capability of the P-47 in terms of range, high altitude performance, payload etc. was basically useless from the Soviet point of view. How well can it cover our ground troops? How well can it escort the Sturmoviks? How well can it handle Bf 109G2 at 3,000 feet?



Well, "a lot of time and effort" is a subjective concept. Are you really suggesting that they couldn't have reorganized priorities and got stronger engines in action more quickly if they had put enough emphasis on it? My argument is that the pace it moved was good enough as long as a Yak-1B can still shoot down Bf 109s.



Right. Which adds up to their being roughly equal.



I never said it was 'better', I said it was 'roughly equal'. Performance was clearly similar, armament was at most slightly inferior, agility was slightly superior and the 202 had slightly better wing loading. It probably came out even. Almost the same speed, climb rate, ceiling, range etc. etc.



Maybe Pinnochio flying some Macchi M.14s?

Ok since you keep bringing it up, per Shores on November 1942, at the end of El Alamein, the actual (as in on-hand strength) TO&E for Italian fighters in the MTO Theater was:

Italians
Macchi 202

54° Stormo - 2
51° Stormo - 23
17° Gruppo CT - 33
153° Gruppo CT - 21
20° Gruppo CT - 11
4° Stormo CT - 28
3° Stormo CT - 20

RE 2001
22° Gruppo Aut CT - 21

Macchi 200
2° Stormo CT was listed as mixed MC 202 and 200 but doesn't list how many
54° stormo CT - 6

G.50bis
24° Gruppo Autonomo CT - 26
160° Gruppo Autonomo CT -7

So that is 138 x MC 202 on hand at that time, 21 x Re 2001, about 15 x MC 200, and 33 x G.50bis for a total of 207 fighters, 75% of which were top quality (MC 202 and Re 2001).

There were also 76 Cr 42s available but at that point they were only used as bombers and mostly flew at night. Very few were ever claimed by 1942 nor did they make any claims.

All this is from Meditteranean Air War Vol III pp 43-46. I think I have an earlier TO&E for them somewhere before the battle in which they had considerably more fighters but I'm having trouble finding it, Shores books lack sorely in useful chapter headings or a real index and being 600+ pages thick are a nuisance to search through trying to find anything.



The thing is if the P-40 dives and is chased by another pilot who really wants him, then at low altitude so long as it can extend sufficiently in the dive to turn around, you now have a new dogfight where the P-40 has a 200 hp advantage, turns better and may be a little faster. This is where a lot of Bf 109s and 202s got shot down. They were better off keeping the fight up above 20k if they could. Sometimes they couldn't such as when their own airbase was attacked.

I think your point about how the Soviets viewed the p47 points out that what is commonly viewed as the "better" fighter
actually often depends on where and who your fighting and how your fighting them.
Pretty sure most people would be quick to say the p47 is vastly superior to an aircobra but maybe not so in all circumstances.

 

[Schweik]

Bingo

 

[XBe02Drvr]

Looks to me like you could put the turbocharger in the belly and add the 2 side scoops back in for the intercooler and oil cooler, give it 1150 HP at 25,000 feet and it should have been fine. The P38 had 4 of those big scoops, 2 on each boom, and it was still fast.

"Turbocharger in the belly." Where? Forward of the instrument panel, behind the cannon ammo, and above the nose gear well? In a wart grafted onto the belly under the wing? Where are you going to route all the ducting? Under the cockpit floor is already taken up with the driveshaft and lots of plumbing. Now you're going to add exhaust going forward and compressed intake air going aft, plus oil, coolant, and intercooler ducting, and you'll have a profile as "pregnant" as a P47, except ninth month rather than sixth. Where are you going to put those cheek cowls? About the only place they'd work would be forward of the cockpit doors in a high pressure, high drag area. That didn't work for the YP, and the laws of physics haven't changed much in the intervening half decade. If you move them aft, they'd have to go behind the engine, generating CG and tailplane aerodynamics problems. The P38 got away with its draggy cheek cowls by placing them aft in a lower pressure area, and then applying LOTS of horsepower.
Cheers,
Wes

 

[Shortround6]

Well, "a lot of time and effort" is a subjective concept. Are you really suggesting that they couldn't have reorganized priorities and got stronger engines in action more quickly if they had put enough emphasis on it? My argument is that the pace it moved was good enough as long as a Yak-1B can still shoot down Bf 109s.

The engine situation was not quite as easy to solve as you seem to think.
The M-105 was derived from the M-100 which was a licenced Hispano back in 1934 or so. Unfortunately a 1933-34 Hispano is a legacy engine from even earlier and in fact shares some dimension/features of the Hispano V-8s of the 1920s.

The Russians had strengthened the engine considerably over the French originals including make the bore 2mm smaller to get thicker cylinder walls. Practically every model in the M-100 to M-105PF-2 series saw them strengthening something.
Something to consider is that before the summer of 1941 the Soviets ability to get 100 octane or better fuel was pretty limited, as was the likelihood of getting such fuel in the future.
At least getting it in the quantities needed for an air force of thousands of planes. This tended to affect engine development.

The M-105 was 35.08 liter engine (2140 cu in) and was bigger than the DB 601 let alone the Allison or Merlin yet they were lighter than those engines. The M-105PF went about 600kg or 1323lbs (the earlier M-105s were 20-30 kg lighter). You would have to beef up quite a few parts to get it to stand up to higher power very well and since it's overhaul life wasn't that good to begin with ( inpart due to the design itself and not due to Soviet workmanship or materials) higher power often shortened the engine life even more.
The fact that the M-105 used a 170mm stroke meant a high piston speed even at a relatively low RPM. The crappy cylinder head (improved over the original French one but not enough) didn't help.
This is why the Soviets were working on the M-106 from 1938 and the M-107 from 1939 and both the Yak 1 and Lagg 1/3 were intended to use these engines from the start. The Engine factories could not bring them to a suitable level of reliability until much later in the war. The M-105PA and the M-105PF were both strengthened and a shorter engine life accepted despite the modified parts. In no way did they simply adjust the boost limit screws and fly on to do battle with the Germans.
The M-105PF got stronger cylinder pins and supercharger drive, the crankshaft was modified, the diameter of the reduction gear;s elastic coupling was changed and it got a new carburetor. on later M-105PFs the crankshaft was further strengthened.

It has been mentioned before, 2000 M-107s were on order and scheduled for completion by the end of 1941. However it took months to get the engine to pass a 50 hour test and only 29 were built in 1941. The engine was problematic for most of it's life and production in peacetime after the war was stopped twice while problems were sorted out. About 7,900 of M-107 wound up being built, the vast majority after the war. Saying that if they had put enough emphasis on it during the war would have solved it's problems seems a little too pat.
In 1946 to get the engine life to hit or exceed 100 hours they changed the propeller reduction ratio, limited the RPM (no mention of what that did to power) and fitted an extra oil pump.
The Russians were also working on the VK-108 engine with two prototypes built in 1943/44 and factory No 26 built a total of 49 prototypes in 1944-46. Work stopped to concentrate on turbo jets.

This is just the engines in one development path, no radials and nothing to do with the AM-35 engines.

Throwing out the M-100/M-105 and starting over would have taken years and might have meant throwing out a lot of the tooling used to make the engines.

Stalin's Idea of motivation did not always produce good results, shooting the two designers of the original 23mm cannon that was to be used by the Lagg and Yak 1 may have provided some motivation to other gun designers but it also may have kept some engineers from taking any big risks and trying for large improvements rather than small increments.

The Germans stumbled too on the later DB 601s and 605s and had to limit their power for months while problems were sorted out.

 

[Shortround6]

The P38 got away with its draggy cheek cowls by placing them aft in a lower pressure area, and then applying LOTS of horsepower.

On the early P-38s The draggy cheek cowls covered the radiators. the intercoolers were in the wing leading edge (not an option for the P-39 because that is where the fuel was) and the oil cooler was under the engine.

 

[Stig1207]

1. An assessment of how well a fighter aircraft did in combat is based on a combination of how many enemy aircraft were destroyed vs. how many friendly aircraft lost. German claims (and overclaiming) are relevant to the latter.
2. The downplaying of Soviet victory rates is based on the notion that they overclaimed far more than anyone else. This is subject to interpretation but is probably substantially overstated. And the ratio of German overclaiming is relevant to the claim.

1. So how many Soviet P-39's were lost based on German claims ?!?
2. So you don't actually know what the Soviet rate off overclaiming was?

 

[Stig1207]

Shurley you're correct that overclaiming distorts the picture of what's really happened.
No disagreement from me there but the discussion was, at least as I understood it, how effective was the p39 compaired to other aircraft, largely the p40 but also various Russian types. Unless there is a great disparity in the overclaiming rates of Russian pilots and those of other nations( and if an average is taken throughout the war they seem to have been similar) then shweiks statement that the Germans overclaimed also meant, at least to me, that in a comparative sense( the only sense that in my mind at least is valid as aircraft did not oparate in a vacuum) the claims cannot just be dismissed as overclaiming and the p39, or any other aircraft concluded as ineffective to whatever degree as one would have to then do the same to every aircraft and you just end right back where you started. Imho

The rate of overclaiming varied by theatre and time period considerably, so I think don't you can assume that they were necessarily similar.

Now let's test your argument; I will readily admit to not knowing how many Hellcats Japanese pilots claimed to have shotdown, but I assume that it was considerably more than the 270 (iirc) the USN reported lost to enemy aircraft. Compared to Japanese claims of Hellcats, I would say that the Hellcat 's 19-1 kill ratio is going to be cosiderably lower and it's wartime record less spectacular.

 

[michael rauls]

The rate of overclaiming varied by theatre and time period considerably, so I think don't you can assume that they were necessarily similar.

Now let's test your argument; I will readily admit to not knowing how many Hellcats Japanese pilots claimed to have shotdown, but I assume that it was considerably more than the 270 (iirc) the USN reported lost to enemy aircraft. Compared to Japanese claims of Hellcats, I would say that the Hellcat 's 19-1 kill ratio is going to be cosiderably lower and it's wartime record less spectacular.

Yes.............. If you only adjust one side for overclaiming it will indeed tilt the picture.

 

[michael rauls]

If Japanese claims of Hellcats were indeed greater than 19 to 1 of actual Hellcat losses (270) that would mean they claimed close to 6000 Hellcats shot down. I'm thinking probably not.